Process of obtaining magnesia.



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No Drawing.

t MULQUGHILIN, 015 SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE-H115" TUFREDERICK DOUGLAS CARTHTEW, OF SAN FRANCISCQ, CALIJFOtI;

POCESS 01E OBTAINING GNESIA.

To all whom it may concern:

Be it known that l, HARRY MGLOUGHLIN, a citizen of the United States,residing at Number 1111 Pine street, in the city and county of SanFrancisco, State of California, have invented new and usefulllmprovements in the Process of Obtaining Magne sia, and of which thefollowing is a specification.

Crude magnesite containing an excess of silica is crushed toapproximately half inch pieces, is then placed in furnace and heated toapproximately 500 (1., or not to exceed 510 C., at which temperatureapproximately all of the CO will be driven off, leaving magnesium oxid,associated with silica. The magnesium oxid has a specific gravity ofabout 3 to 3.6, while the silica has a specific gravity of ap roximately2.2. This will then admit of sufiicient diflerence to allow a separationbeing made either by currents of water or air, in accordance with thewell known classification rinciple.

After leaving the n the materials are rapidly cooled, by being passedinto a cooling chamber in which the temperature is kept very low, orpreferably it may be cooled by immersion in water in which thedifierence of the contraction of the quartz and magnesium oxid by thecooling is utilized tor disintegration of the lumps, thereby freeing themagnesia from the silica. The product is then passed into an agitatorwhich by attrition of the particles will to a great extent further treethe silicious parti- Specification of Letters Patent.

Patented Deco d, 11th Application filed. February 9, 1916. Serial No.77,2 lfi l.

cles from the magnesia. llt is then passed over screens which screen outthe coarser crystalline silica from the finer magnesia and from this thematerial passes to a series of grinders in which the material ispulverized to approximatel mesh. ][t is then subjected to elutriatlon ina current of air or water, when the silica existing either as quartz ormagnesium silicate with a spe cific gravity of approximately 2.2 will beseparated from the magnesium oxid having a specific gravity of 3 to 3.6.This leaves only a very small proportion of the silica (either free oras magnesium silicate) remaining in the magnesia product.

What I claim is:

The process substantially as herein described, of producing a relativelypure magnesium oxid from a magnesite containing silica, which comprisesfirst calcining the material at a temperature suflicient to drive offsubstantially all the carbon dioxid, quenching the hot mass, whereby themagnesia is disintegrated, sieving out the coarse silica, grinding theresidue to pass a 30 mesh screen, and finally subjecting the residue toregulated fluid currents of suflicient strength to carry away thematerial havin a specific gravity of approximately 2.2 an of insumcientstrength to carry away the material having a specific ravity of 3 ormore! H RRY MCLOUGIHJIN.

Witnesses:

WM. P. Humane, M. all NGER.

